Air filter device

ABSTRACT

An air-purifying filter device for a sealed optical enclosure of a luminaire comprises a coherent mass of activated charcoal particles contained in a rigid holder and having a plurality of recesses in its surface to increase the filter surface area, lower its air flow resistance, and reduce the amount of contaminant deposit thereon. The filter device is arranged in an enclosure formed by separable connecting parts of the luminaire in communication with the sealed optical enclosure.

United States Patent 1 95,009 Osteen 1 Oct. 3, 1972 [54] AIR FILTERDEVICE 3,272,978 9/1963 Jackson ..240/52 X 72 Inventor: Mitchell M.Osteen, Rte. 1, Zir- 2 32%: 2:32: 5"

conia N.C lice 2,614,650 10/1952 Chandler et a1. ..55/387 X [22] Filed:March 30, 1970 FOREIGN PATENTS OR APPLICATIONS [21] Appl. No.: 23,912

674,562 9/1933 Germany ..55/DIG. 33

52 U.S. Cl. ..55/385, 55/387, 55/504, mm Examine, F,ank w, Lune, 5240/25, 240/47 Assistant Examiner-Vincent Gifford [5 1t. Cl.Attorney-Sidney Greenberg, Wesley Haubner Field Of arch ..55/385, 387, 40, 4 4, 512, Frank L. Neuhauser, Oscar B. Waddell and Joseph55/5l4,5l6,517,518,519, 524,510; Forman [57] ABSTRACT [56] Referencescued An air-purifying filter device for a sealed optical en- UNITEDSTATES PATENTS closure of a luminaire clomprises a coherent mass ofactivated charcoal partic es contained in a rigid holder Mlll'Oy-.- Xand having a plurality of recesses in surface to Karlstrom crease thefilter surface area lower its air flow 2,553,763 5/ 1951 Hammon ..55/518X sistance, and reduce the amount of contaminant 3,377,480 4/1968Robertson deposit thereon The filter device i arranged in an 1,506,2168/1924 Benner ..55/518 X closure formed by separable connecting parts ofthe 3,352,423 11/1967 08161111311 ..210/497X lmninaire in communicationwith the Sealed optical 2,583,812 1/1952 Briggs et a1. ..55/524 UXenclosure. 3,458,977 8/1969 Young et a1. ..55/514 X 1,412,748 4/1922McKay ..339/120 X 3 Claims, 4 Drawing Figures PATENTEDncI 3 m2 SHEET 2[IF 4 0. m m M.

AIR FILTER DEVICE The present invention relates to air filters andparticularly concerns an improved air filter device for use inluminaires having sealed optical systems protected from the entry ofcontaminating materials in the atmosphere.

It is an object of the present invention to provide an improvedair-permeable filter device for purifying the air entering sealedluminaire optical systems, whereby a high level of illumination may beobtained from the luminaire over a prolonged period.

It is a particular object of the invention to provide an air filterdevice of the above type which has reduced resistance to air flowtherethrough during its operating life, is mechanically strong andwithstands rough handling, has increased filtering surface area, and isrelatively easy to manufacture and assemble in proper position in aluminaire.

It is another object of the invention to provide an improved arrangementof an air filter of the above type in a luminaire where in the filterdevice is shielded from direct exposure to dust and the high temperatureand radiation of the luminaire lamp.

. Other objects and advantages will become apparent from the followingdescription and the appended claims.

With the above objects in view, the present invention in one of itsaspects relates to a filter device comprising tubular holder meanshaving openings at opposite ends, and a mass of filter materialcontained in and held by the holder means and having opposite surfacesthrough which air may pass for purification by the filter material, themass of filter material being formed with recess means extending asubstantial distance partially into the mass of filter material. In apreferred embodiment of the invention, the described air filter deviceis used in combination with a luminaire optical assembly comprising ahousing, a reflector and a light transmitting closure means securedtogether in sealed relation forming a closed optical enclosure, theoptical assembly being separably connected to a supporting means andforming a second enclosure therewith at the connecting region, thefilter device being arranged in the second enclosure in communicationwith the interior of the closed optical enclosure and with its recessedsurface exposed to the incoming air flow for filtering the same.

The invention will be better understood from the following descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a view in elevation, partly broken away, of a luminaire ofindustrial type in which the invention may be embodied;

FIG. 2 is an exploded view in perspective of the slidable connectingdevice of the FIG. 1 luminaire incorporating an air filter in accordancewith the invention;

FIG. 3 is an exploded view of the air filter arrangement in the FIG. 2luminaire connecting device; and

FIG. 4 is a cross-sectional view of the assembly of the air filterdevice with the luminaire socket housing.

Referring now to the drawings, and particularly to FIG. 1, there isshown an industrial luminaire comprising a ballast housing 1 secured toa wire conduit 2 such as a metal pipe and having an optical assembly 3suspended from the bottom thereof. Contained is a transformer 4 andother electrical operating components (not shown) for operating thelight source of the luminaire. Optical assembly 3 is detachably securedto ballast housing 1 by means of a quick disconnect device comprisingco-acting support members 9 and 10 which, when assembled as shown,provide an enclosure for the electrical and mechanical connectingstructure and the air filter device of the invention, as shown in FIGS.2 and 3. The structure and arrangement of connecting members 9, 10 aremore fully disclosed in copending application, Ser. No. 882,886, Osteenet al., filed Dec. 8, 1969 and assigned to the same assignee as thepresent invention. Optical assembly 3 includes a faceted reflector 5 inwhich is mounted lamp 6, typically of high intensity gaseous dischargetype such as a mercury vapor lamp, removably secured to a lampholder orsocket 7 so as to extend downwardly therefrom into reflector 5.Lampholder 7 is secured within socket housing 8 which is joined to thetop of reflector 5 by spaced legs 8a defining circumferentially spacedopenings which are closed by an annular transparent window 11 to permitlight from lamp 6 to pass upwardly out of the luminaire. The mouth ofreflector 5 is closed by a hinged transparent door glass 12. Upperwindow 11 is suitably sealed, e.g., by resilient gaskets (not shown), atits top to socket housing 8 and at its bottom to reflector 5, and doorglass 12 when closed is similarly sealed to the bottom rim of reflector5 to provide an air-tight enclosure within optical assembly 3. Such anarrangement is shown in US. Pat. No. 3,457,399, Milroy wherein is alsodisclosed a luminaire air filter device and arrangement on which thepresent invention is an improvement.

As seen in FIG. 2, the quick disconnect device of the luminaire by whichoptical assembly 3 is suspended from the bottom of ballast housing 1comprises slidably inter-engageable support members 9 and 10, of whichmember 10 is fixed to the bottom of ballast housing 1 and member 9 isformed at the top of socket housing 8.

Hanger 10 is an inverted channel-shaped member secured by suitable meansto the bottom wall of ballast housing 1 and formed along its lower edgeswith spaced parallel flanges 10a and 10b. The rear end of member 10 isclosed by plate 13 secured by screws 14 which engage elongated bosses15, 15a of C-shaped cross-section formed along the inner surfaces of thesides of member 10. Secured to the top wall of member 10 adjacent coverplate 13 is an electrical receptacle 16 comprising an insulated sockethousing having a pair of spaced sockets in which are located electricalcontacts,

16a suitably connected by lead wires 17 to the electrical operatingcomponents in ballast housing 1.

Complementary connecting device 9 at the top of optical assembly 3 isformed with spaced parallel flanges or runners 9a, 9b formed to engageover and slide along hanger flanges 10a, 10b of hanger member 10. Whenconnecting device 9 is slid completely into the latter member, opticalassembly 3 hangs from hanger 10. At the rear end of connecting device 9is a vertical plate 9f which closes the open end of channel member 10when connecting device 9 is fully slid into the latter, thereby forminga complete housing enclosure for the interconnected parts. In thisassembled position, connector 9 is fastened to hanger member 10 by ascrew or other suitable means engaging boss 19 for locking the two partstogether.

= and apertures 320 of top Mounted on the surface of member 9 betweenflanges 9a, 9b is an electrical plug 9c having spaced electrical contactprongs 9e, 9d which fit into the spaced sockets of electrical receptaclel6 and engage the resilient contact members 16a therein, so that whenmember 9 is fully slid into channel member 10, electrical connectionbetween the parts is automatically made. Suitablelead wires (not shown)connect contact prongs 9e, 9d to lampholder 7.

Luminaires of the described type are particularly applicable for indooruse in industrial environments such as manufacturing plants andfactories. In such areas, the atmospheres often contain various types ofcontaminants particularly of gaseous nature which tend to adverselyaffect the optical and illuminating system of the luminaire, and in theusual installation ready cleaning of the luminaire is difficult toaccomplish due to the relatively inaccessible location of suchluminaires.

In accordance with the invention, an improved filter arrangement isprovided for such luminaires. In the illustrated embodiment, filterdevice 30 is arranged in the space between vertical plate 9f andelectrical plug 90 at the top of socket housing 8 (see FIGS. 2 and 3).As seen best in FIG. 3, the top of socket housing 8 is integrally formedwith a box-like receptacle 8b having an opening 80 in which filterdevice 30 is received and having an aperture 8d at its bottom (see FIG.4) whereby opening 8c communicates with the interior of socket housing 8and the sealed optical enclosure. Filter device 30 comprises anair-permeable mass of filter material 31. Typically, the filter materialis a bonded coherent mass of activated charcoal particles through whichthe air passes and which serves to remove therefrom, by adsorption,contaminants not only of particulate type but also of gaseous type, suchas found in industrial fumes, smog, exhaust products from internalcombustion engines such as hydrocarbons, and the like. In accordancewith a feature of the invention, filter mass 31 is contained and held ina rigid housing 32 which is preferably of metal, such as aluminum, butmay also be made of a hard plastic material such as a phenolic resin. Inthe illustrated embodiment, filter holder or housing 32 comprises atubular portion 32a open at its bottom and filled with filter material,anda flat apertured plate 32b extending across the top of tubularportion 32a. The latter portion has a shape complementary to the opening80 in receptacle 8b so as to fit loosely therein, and in the assembly,plate 32b rests on the rim of receptacle 8b and is suitably securedthereto in sealing relation by screws 34 or the like with a resilientgasket 33 interposed therebetween. With the parts in assembledcondition, filter device 30 is enclosed by connecting structure 9, l andis thereby protected from direct exposure to dust, heat and harmfulradiation from the lamp, while operating as the sole passageway for airinto and out of the optical assembly.

, In accordance with another feature of the invention, filter mass 31 isformed with a plurality of spaced recesses 31a (see FIG. 4) extending asubstantial distance from its top surface partially into its interior,plate 32b are arranged in re gister with the openings of recesses 31aand are respectively substantially co-extensive therewith to enableentry of air through filter holder 32 into filter mass 31. As will beseen in FIG. 4, recesses 31a extend more than halfway between theopposite surfaces of filter mass 32. The provision of such elongatedrecesses 3la in the described arrangement results in a considerablylarger breathing surface of the filter mass 31 with minimum exposure tothe outside environment. The recesses further act as settling chambersfor entering dirt particles, and even if the filter device is orientedin various positions only a relatively small portion of the filersurface area is subject to contaminant deposits. It is accordinglyevident that the provision of the filter recesses as described not onlydecreases the initial resistance to air flow through the filter, butalso ,considerably enhances the probability of continued low air flowresistance for a prolonged period of luminaire operating life.

A cross-sectional view of the filter device 30 in assembly with sockethousing 8 is shown in FIG. 4, the lampholder and-associated parts insocket housing 8 being omitted for the sake of clarity. As there seen,the bottom surface of filter mass 31 is spaced somewhat from the bottomof receptacle 8b to permit unimpeded air flow between filter 31 andaperture 8d in the top of socket housing 8. A series of elongatedrecesses 31a spaced along the central portion of filter mass 31 andaligned with corresponding apertures 320 of plate 32b extend downwardlyinto the interior of the filter mass, while recesses 31b at the marginsof filter mass 31 in re gister with apertures 32d of plate 32b extend toa lesser distance into filter mass 31 and serve a similar function asrecesses 31a, as described above. Apertures 32d of the filter plate areso formed as to provide a stepped or ledge portion 32e at the bottom ofeach aperture 32d projecting inwardly into the interior of holder 32,and as more fully described below, filter mass 31 is so introduced intothe filter holder as to overlie the ledge portions 32e to interlock thefilter mass with the holder. In addition, filter mass 31 is adhesivelybonded to the inner surfaces of tubular holder 32.

In a suitable procedure for making a filter device such as described,activated charcoal in granular form having a particle size within US.sieve sizes 20 to 50 is thoroughly mixed with a suitable binder materialof known type, either organic or inorganic, and with the application ofany necessary heat to properly distribute the binder material in thecharcoal mass and/or partially cure the binder, the mixture isintroduced into the open end of an aluminum holder such as member 32having steel pins (not shown) inserted into the apertures in the flatplate thereof at its opposite end. The pins in the side apertures 32dare inserted only partially therein so as to leave a space for thefilter mass to flow into so as to provide the mechanical interlock withthe stepped portions 32e of holder 32, as previously mentioned. The pinsplaced in the central apertures 32c are inserted to the desired depth ofthe recesses to be formed thereby. After the rigid holder is filled withthe filter mixture, the latter material is pressed into the holdercavity to compact it and ensure its flow over the stepped holderportions 32e, as well as to space the outer surface inwardly of the rimof .the rigid holder. The pins in the holder apertures are thenimmediately removed and the bonded filter mass allowed to harden.

While in the particular embodiment illustrated only one surface offilter mass 31 is provided with recesses, it will be understood that theopposite surface may also have recesses which do not communicate withthe recesses of the other surface or open on the latter surface. Such anarrangement may be used, for example, where it is desired to make thefilter device (with a suitable holder therefor) reversible for exposingeither of the filter surfaces to the incoming air.

It will also be understood that while the filter device has beendescribed as used in connection with a sealed luminaire optical system,it may have application to a wide variety of other devices and apparatuswhere the use of such air filters is desirable or necessary.

While the present invention has been described with reference toparticular embodiments thereof, it will be understood that numerousmodifications may be made by those skilled in the art without actuallydeparting from the scope of the invention. Therefore, the appendedclaims are intended to cover all such equivalent variations as comewithin the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a luminaire, an optical assembly comprising a housing, a reflectorand light transmitting closure means secured together in sealed relationforming a closed optical enclosure, means for mounting a lamp in saidenclosure, and an air-filter device arranged on said closed opticalclosure communicating with the interior thereof, said air-filter devicecomprising rigid tubular holder means having openings at opposite ends,and a mass of filter material contained in and held by said rigid holdermeans and having opposite surfaces through which air may pass forpurification by said filter material, said mass of said filter materialbeing formed with elongated recess means extending from one of saidsurfaces partially into said mass of filter material more than halfwaybetween said opposite surfaces thereof, said elongated recess meansbeing entirely exposed to the incoming air flow for filtering the airpassing thereinto by removal of solid and gaseous impurities containedin the air, said recess means comprising a plurality of recesses havingopenings on said one surface of said mass of filter material, saidtubular holder means of having a rigid transverse plate portion at oneend covering said recessed filter surface so that said holder meansforms a cup-shaped container for said filter material, said rigid plateportion having a number of apertures corresponding to the number of saidrecess openings, each said recess opening being in register andsubstantially co-extensive with one of said apertures. I

2. A device as defined in claim 1, said rigid tubular holder means beingformed with ledge portions in the interior thereof projecting into saidmass of filter material for locking the same within said holder means.

3. A device as defined in claim 1, said housing having an outer surfaceformed with first connecting means and a receptacle for mounting saidair-filter device, and supporting means for supporting said opticalassembly having second connecting means complementary to and slidablyengageable with said first connecting means and defining therewith asecond enclosure enclosing said air-filter device.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3,695,009 DatedOCTOBER 3,1 2

Patent No.

Inventor(s) M. M OSTEEN It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

IN THE HEAD'ING, THE ASSIGNEE GENERAL ELEcTRIc COMPANY SHOULD BE sHowNCoL. 1, LINE 66 AFTER "coNTAINEo" INSERT wITIIIN BALLAST HOUSING 1 ICoL. 1, LINE 2 "32" SHOULD BE 31 CoL. LINE 9 "FILER" SHOULD BE FILTERSigned and sealed this 13th day of March 1973.

(SEAL) Attest:

EDWARD M. FLETCHER,JR ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

1. In a luminaire, an optical assembly comprising a housing, a reflectorand light transmitting closure means secured together in sealed relationforming a closed optical enclosure, means for mounting a lamp in saidenclosure, and an air-filter device arranged on said closed opticalclosure communicating with the interior thereof, said air-filter devicecomprising rigid tubular holder means having openings at opposite ends,and a mass of filter material contained in and held by said rigid holdermeans and having opposite surfaces through which air may pass forpurification by said filter material, said mass of said filter materialbeing formed with elongated recess means extending from one of saidsurfaces partially into said mass of filter material more than halfwaybetween said opposite surfaces thereof, said elongated recess meansbeing entirely exposed to the incoming air flow for filtering the airpassing thereinto by removal of solid and gaseous impurities containedin the air, said recess means comprising a plurality of recesses havingopenings on said one surface of said mass of filter material, saidtubular holder means of having a rigid transverse plate portion at oneend covering said recessed filter surface so that said holder meansforms a cup-shaped container for said filter material, said rigid plateportion having a number of apertures corresponding to the number of saidrecess openings, each said recess opening being in register andsubstantially co-extensive with one of said apertures.
 2. A device asdefined in claim 1, said rigid tubular holder means being formed withledge portions in the interior thereof projecting into said mass offilter material for locking the same within said holder means.
 3. Adevice as defined in claim 1, said housing having an outer surfaceformed with first connecting means and a receptacle for mounting saidair-filter device, and supporting means for supporting said opticalassembly having second connecting means complementary to and slidablyengageable with said first connecting means and defining therewith asecond enclosure enclosing said air-filter device.